From nobody Fri Dec 19 20:35:54 2025 Received: from mout-p-101.mailbox.org (mout-p-101.mailbox.org [80.241.56.151]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) by smtp.subspace.kernel.org (Postfix) with ESMTPS id 83CD425F7A7; Fri, 25 Apr 2025 15:02:11 +0000 (UTC) Authentication-Results: smtp.subspace.kernel.org; arc=none smtp.client-ip=80.241.56.151 ARC-Seal: i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1745593333; cv=none; b=qrc1ibZdbv5fdgZ0byoFVBUlMcq3Q97Rs7FmswEUxzQFnBKFOYfOru0YO2CNmUrmEHSjXkqG/Zo0KYH/J8ukncxJJFQp0rzcyPDYSZLFRtac4uxfs5D277KqApqZGdUbGXtWi7Z+pHtyPufh2ayWxDstgBvyN8cnAFR59AKysCg= ARC-Message-Signature: i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1745593333; c=relaxed/simple; bh=apsOcyCRGG4zui5ahb4QBp/DW5Zg8A1uNMLm3N7c5jI=; h=From:To:Cc:Subject:Date:Message-ID:In-Reply-To:References: MIME-Version; b=TWNsv4tblpg9BaWnSn2H7tl+/l2898Ewa0+Ka3SZE/VQTjXlitK0xkJCPuBJ4jcoXFUHRD0Y2k0Ft8zNHO2Z2PrChR8K1qN0O19A9EMWBPorqZ5DZf6Z/iwNrj696IY1sYDHeFlNnRCHnbvsAQDSnqHxwTa/CpY+3JB1T2/lvM4= ARC-Authentication-Results: i=1; smtp.subspace.kernel.org; dmarc=none (p=none dis=none) header.from=buenzli.dev; spf=pass smtp.mailfrom=buenzli.dev; arc=none smtp.client-ip=80.241.56.151 Authentication-Results: smtp.subspace.kernel.org; dmarc=none (p=none dis=none) header.from=buenzli.dev Authentication-Results: smtp.subspace.kernel.org; spf=pass smtp.mailfrom=buenzli.dev Received: from smtp202.mailbox.org (smtp202.mailbox.org [IPv6:2001:67c:2050:b231:465::202]) (using TLSv1.3 with cipher TLS_AES_256_GCM_SHA384 (256/256 bits) key-exchange X25519 server-signature RSA-PSS (4096 bits) server-digest SHA256) (No client certificate requested) by mout-p-101.mailbox.org (Postfix) with ESMTPS id 4ZkbfK5TnFz9t1w; Fri, 25 Apr 2025 17:02:01 +0200 (CEST) From: Remo Senekowitsch To: Rob Herring , Saravana Kannan , Miguel Ojeda , Alex Gaynor , Boqun Feng , Gary Guo , =?UTF-8?q?Bj=C3=B6rn=20Roy=20Baron?= , Benno Lossin , Andreas Hindborg , Alice Ryhl , Trevor Gross , Danilo Krummrich , Greg Kroah-Hartman , "Rafael J. Wysocki" , Dirk Behme , Remo Senekowitsch Cc: linux-kernel@vger.kernel.org, devicetree@vger.kernel.org, rust-for-linux@vger.kernel.org Subject: [PATCH v3 2/7] rust: property: Enable printing fwnode name and path Date: Fri, 25 Apr 2025 17:01:25 +0200 Message-ID: <20250425150130.13917-3-remo@buenzli.dev> In-Reply-To: <20250425150130.13917-1-remo@buenzli.dev> References: <20250425150130.13917-1-remo@buenzli.dev> Precedence: bulk X-Mailing-List: linux-kernel@vger.kernel.org List-Id: List-Subscribe: List-Unsubscribe: MIME-Version: 1.0 Content-Transfer-Encoding: quoted-printable X-Rspamd-Queue-Id: 4ZkbfK5TnFz9t1w Content-Type: text/plain; charset="utf-8" Add two new public methods `display_name` and `display_path` to `FwNode`. They can be used by driver authors for logging purposes. In addition, they will be used by core property abstractions for automatic logging, for example when a driver attempts to read a required but missing property. Signed-off-by: Remo Senekowitsch --- rust/kernel/device/property.rs | 78 ++++++++++++++++++++++++++++++++++ 1 file changed, 78 insertions(+) diff --git a/rust/kernel/device/property.rs b/rust/kernel/device/property.rs index d89715f7d..28850aa3b 100644 --- a/rust/kernel/device/property.rs +++ b/rust/kernel/device/property.rs @@ -49,6 +49,84 @@ pub(crate) fn as_raw(&self) -> *mut bindings::fwnode_han= dle { self.0.get() } =20 + /// Returns an object that implements [`Display`](core::fmt::Display) = for + /// printing the name of a node. + pub fn display_name(&self) -> impl core::fmt::Display + '_ { + struct FwNodeDisplayName<'a>(&'a FwNode); + + impl core::fmt::Display for FwNodeDisplayName<'_> { + fn fmt(&self, f: &mut core::fmt::Formatter<'_>) -> core::fmt::= Result { + // SAFETY: self is valid by its type invariant + let name =3D unsafe { bindings::fwnode_get_name(self.0.as_= raw()) }; + if name.is_null() { + return Ok(()); + } + // SAFETY: fwnode_get_name returns null or a valid C strin= g and + // name is not null + let name =3D unsafe { CStr::from_char_ptr(name) }; + write!(f, "{name}") + } + } + + FwNodeDisplayName(self) + } + + /// Returns an object that implements [`Display`](core::fmt::Display) = for + /// printing the full path of a node. + pub fn display_path(&self) -> impl core::fmt::Display + '_ { + struct FwNodeDisplayPath<'a>(&'a FwNode); + + impl core::fmt::Display for FwNodeDisplayPath<'_> { + fn fmt(&self, f: &mut core::fmt::Formatter<'_>) -> core::fmt::= Result { + // The logic here is the same as the one in lib/vsprintf.c + // (fwnode_full_name_string). + + let num_parents =3D unsafe { bindings::fwnode_count_parent= s(self.0.as_raw()) }; + + for depth in (0..=3Dnum_parents).rev() { + let fwnode =3D if depth =3D=3D 0 { + self.0.as_raw() + } else { + // SAFETY: `self.0.as_raw()` is valid + unsafe { bindings::fwnode_get_nth_parent(self.0.as= _raw(), depth) } + }; + + // SAFETY: fwnode is valid, it is either `self.0.as_ra= w()` or + // the return value of `bindings::fwnode_get_nth_paren= t` which + // returns a valid pointer to a fwnode_handle if the p= rovided + // depth is within the valid range, which we know to b= e true. + let prefix =3D unsafe { bindings::fwnode_get_name_pref= ix(fwnode) }; + if !prefix.is_null() { + // SAFETY: fwnode_get_name_prefix returns null or a + // valid C string + let prefix =3D unsafe { CStr::from_char_ptr(prefix= ) }; + write!(f, "{prefix}")?; + } + // SAFETY: fwnode is valid for the reasons stated above + let name =3D unsafe { bindings::fwnode_get_name(fwnode= ) }; + if !name.is_null() { + // SAFETY: fwnode_get_name returns null or a valid + // C string + let name =3D unsafe { CStr::from_char_ptr(name) }; + write!(f, "{name}")?; + } + + if depth !=3D 0 { + // SAFETY: `fwnode` is valid, because `depth` is + // a valid depth of a parent of `self.0.as_raw()`. + // `fwnode_get_nth_parent` increments the refcount= and + // we are responsible to decrement it. + unsafe { bindings::fwnode_handle_put(fwnode) } + } + } + + Ok(()) + } + } + + FwNodeDisplayPath(self) + } + /// Checks if property is present or not. pub fn property_present(&self, name: &CStr) -> bool { // SAFETY: By the invariant of `CStr`, `name` is null-terminated. --=20 2.49.0